When certain liquids are subjected to reduction in pressure of an appropriate duration and magnitude, small pre-existing bubbles of gas and vapor in the liquids expand to some maximum size and then collapse with great violence. This phenomenon is called cavitation and, when properly controlled, causes very high energy densities to occur both within the bubbles and in the surrounding liquid. The invention disclosed hereinafter relates to a device called a cavitation fusion reactor (CFR), which uses cavitation of a liquid metal to bring about thermonuclear fusion of hydrogen isotopes and other liquid (low Z) elements, both within a bubble created in the host liquid (metal), and in the surrounding host liquid. In its normal operation a reactor of this type produces one or more of the following: the release of energy which is removed as heat; the creation of elements, such as tritium or helium-3, that can be used as thermonuclear fuel, either in the CFR itself in a regenerative manner or in some other fusion device; the fission of heavy elements distributed in the liquid metal; and the radiation of neutrons.
In what follows, as asterisk (*) used on a symbol for a physical quantity denotes a quantity that is in some system of units. Thus, R.sub.n * denotes the equivalent or equilibrium radius of a bubble in centimeters. The symbol R* is the time-varying radius of the bubble in centimeters. The symbol, R, is the non-dimensional radius of a bubble and is defined by R=R*/R.sub.n *. The absence of an asterisk denotes a non-dimensional quantity. The words "negative pressure" will mean a reduction of the ambient pressure in the liquid metal by an applied pressure, which may or may not make the total pressure less than zero. The small bubbles from which cavitation starts will be called "seeds", the liquid in which the cavitation takes place will be called the "host liquid", and a method of obtaining a specified distribution of seeds will be called "seeding" the host liquid. A very small seed containing N moles of gas may be lodged on a minute particle and not have a spherical shape. The term, "equivalent radius", R.sub.n *, will be used to denote the radius of a spherical bubble containing the same number of moles of gas at the same ambient temperature and pressure in the host liquid. For a spherical bubble at rest in a liquid, the terms "equivalent radius" and "equilibrium radius" are identical. The cycle of expansion and contraction that a bubble undergoes under the influence of an applied pressure field will be called a "cavitation event", and the region in the host liquid where these events occur will be called the "cavitation zone". Seeds may be a random distribution of very small bubbles with some average equivalent radius (say, of the order of 10.sup. -5 or 10.sup.-4 cm.) or may be distribution of larger bubbles whose equivalent radii fall in a specified range. The words "bubble" and "cavity" used herein are synonyms.
Two main types of cavitation fusion reactors are described hereinafter: the Type I CFR, which maximizes the production of energy and other useful products through thermonuclear fusion in the host liquid; and the Type II CFR, which maximizes the production of tritium and other useful products through thermonuclear fusion within the bubbles in the host liquid.
Both types of cavitation fusion reactors may be operated in a mode which produces little or no radioactive products. In this mode the reaction is between lithium nuclei and ordinary hydrogen (.sub.1 H.sup.1 or h) nuclei. In alternative modes of operation the devices use deuterium (.sub.1 H.sup.2 or d), tritium (.sub.1 H.sup.3 or t), or a mixture of both d and t as the H-isotope fuel, and the liquid metal may be lithium, beryllium, aluminum, tin, indium, thallium or some other element or alloy. Deuterium is the heavy hydrogen isotope (H-isotope) that occurs in nature, while tritium, the other heavy H-isotope, does not. Only deuterium need be supplied from an external source in both the start-up phase and steady-state operation of the Type I CFR or a Type II CFR. Type I CFR uses a mixture of deuterium and tritium in order to yield a net gain of energy that can be transformed into useful work. The required inventory of tritium is produced within the reactor by the fusion of deuterium nuclei and the interaction of neutrons with lithium or lithium alloyed with beryllium. In a similar manner, a Type II CFR may operate as a generator of tritium that requires only deuterium as the externally supplied fuel.
Once a CFR of either type is placed in operation, the reactor will "breed" its own tritium; that is, the reactor will produce more tritium than it burns, no matter whether or not the fusion reactions start with deuterium alone or with a mixture of deuterium and tritium.